I also use SyncToy. But I use it to sync two full drives between PCs. It’s my own little way of “mirroring” a drive that holds critical data. Used to just use Raid1 but after the kids accidently deleting some files, I discovered a Mirror didn’t work so great. 🙂
That led me to SyncToy, splitting the two drives among two PCs that are “always on” anyway. Sync ’em up, and then use Carbonite for one of them to back up to the web.
I’ve also used AllWaySync which also works VERY well. You may want to check them out too as it’s more customizable then SyncToy. It’s also free for personal use.